Oximyl macrocyclic derivatives

ABSTRACT

The present invention relates to compounds of Formula I, or pharmaceutically acceptable salts, esters, or prodrugs thereof: 
                         
which inhibit serine protease activity, particularly the activity of hepatitis C virus (HCV) NS3-NS4A protease. Consequently, the compounds of the present invention interfere with the life cycle of the hepatitis C virus and are also useful as antiviral agents. The present invention further relates to pharmaceutical compositions comprising the aforementioned compounds for administration to a subject suffering from HCV infection. The invention also relates to methods of treating an HCV infection in a subject by administering a pharmaceutical composition comprising a compound of the present invention.

RELATED APPLICATIONS

This application claims the benefit of U.S. provisional application No. 60/992,578 filed on Dec. 5, 2007. The contents of the above application are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to macrocycles having activity against the hepatitis C virus (HCV) and useful in the treatment of HCV infections. More particularly, the invention relates to oximyl macrocyclic compounds, compositions containing such compounds and methods for using the same, as well as processes for making such compounds.

BACKGROUND OF THE INVENTION

HCV is the principal cause of non-A, non-B hepatitis and is an increasingly severe public health problem both in the developed and developing world. It is estimated that the virus infects over 200 million people worldwide, surpassing the number of individuals infected with the human immunodeficiency virus (HIV) by nearly five fold. HCV infected patients, due to the high percentage of individuals inflicted with chronic infections, are at an elevated risk of developing cirrhosis of the liver, subsequent hepatocellular carcinoma and terminal liver disease. HCV is the most prevalent cause of hepatocellular cancer and cause of patients requiring liver transplantations in the western world.

There are considerable barriers to the development of anti-HCV therapeutics, which include, but are not limited to, the persistence of the virus, the genetic diversity of the virus during replication in the host, the high incident rate of the virus developing drug-resistant mutants, and the lack of reproducible infectious culture systems and small-animal models for HCV replication and pathogenesis. In a majority of cases, given the mild course of the infection and the complex biology of the liver, careful consideration must be given to antiviral drugs, which are likely to have significant side effects.

Only two approved therapies for HCV infection are currently available. The original treatment regimen generally involves a 3-12 month course of intravenous interferon-α (IFN-α), while a new approved second-generation treatment involves co-treatment with IFN-α and the general antiviral nucleoside mimics like ribavirin. Both of these treatments suffer from interferon related side effects as well as low efficacy against HCV infections. There exists a need for the development of effective antiviral agents for treatment of HCV infection due to the poor tolerability and disappointing efficacy of existing therapies.

In a patient population where the majority of individuals are chronically infected and asymptomatic and the prognoses are unknown, an effective drug would desirably possess significantly fewer side effects than the currently available treatments. The hepatitis C non-structural protein-3 (NS3) is a proteolytic enzyme required for processing of the viral polyprotein and consequently viral replication. Despite the huge number of viral variants associated with HCV infection, the active site of the NS3 protease remains highly conserved thus making its inhibition an attractive mode of intervention. Recent success in the treatment of HIV with protease inhibitors supports the concept that the inhibition of NS3 is a key target in the battle against HCV.

HCV is a flaviridae type RNA virus. The HCV genome is enveloped and contains a single strand RNA molecule composed of circa 9600 base pairs. It encodes a polypeptide comprised of approximately 3010 amino acids.

The HCV polyprotein is processed by viral and host peptidase into 10 discreet peptides which serve a variety of functions. There are three structural proteins, C, E1 and E2. The P7 protein is of unknown function and is comprised of a highly variable sequence. There are six non-structural proteins. NS2 is a zinc-dependent metalloproteinase that functions in conjunction with a portion of the NS3 protein. NS3 incorporates two catalytic functions (separate from its association with NS2): a serine protease at the N-terminal end, which requires NS4A as a cofactor, and an ATP-ase-dependent helicase function at the carboxyl terminus. NS4A is a tightly associated but non-covalent cofactor of the serine protease.

The NS3-NS4A protease is responsible for cleaving four sites on the viral polyprotein.

The NS3-NS4A cleavage is autocatalytic, occurring in cis. The remaining three hydrolyses, NS4A-NS4B, NS4B-NS5A and NS5A-NS5B all occur in trans. NS3 is a serine protease which is structurally classified as a chymotrypsin-like protease. While the NS serine protease possesses proteolytic activity by itself, the HCV protease enzyme is not an efficient enzyme in terms of catalyzing polyprotein cleavage. It has been shown that a central hydrophobic region of the NS4A protein is required for this enhancement. The complex formation of the NS3 protein with NS4A seems necessary to the processing events, enhancing the proteolytic efficacy at all of the sites.

A general strategy for the development of antiviral agents is to inactivate virally encoded enzymes, including NS3, that are essential for the replication of the virus. Current efforts directed toward the discovery of NS3 protease inhibitors were reviewed by S. Tan, A. Pause, Y. Shi, N. Sonenberg, Hepatitis C Therapeutics: Current Status and Emerging Strategies, Nature Rev. Drug Discov., 1, 867-881 (2002).

SUMMARY OF THE INVENTION

The present invention relates to modified oximyl macrocyclic compounds and pharmaceutically acceptable salts, esters or prodrugs thereof, and methods of using the same to treat hepatitis C infection in a subject in need of such therapy. Macrocyclic compounds of the present invention interfere with the life cycle of the hepatitis C virus and are also useful as antiviral agents. The present invention further relates to pharmaceutical compositions comprising the aforementioned compounds, salts, esters or prodrugs for administration to a subject suffering from HCV infection. The present invention further features pharmaceutical compositions comprising a compound of the present invention (or a pharmaceutically acceptable salt, ester or prodrug thereof) and another anti-HCV agent, such as interferon (e.g., alpha-interferon, beta-interferon, consensus interferon, pegylated interferon, or albumin or other conjugated interferon), ribavirin, amantadine, another HCV protease inhibitor, or an HCV polymerase, helicase or internal ribosome entry site inhibitor. The invention also relates to methods of treating an HCV infection in a subject by administering to the subject a pharmaceutical composition of the present invention. The present invention further relates to pharmaceutical compositions comprising the compounds of the present invention, or pharmaceutically acceptable salts, esters, or prodrugs thereof, in combination with a pharmaceutically acceptable carrier or excipient.

In one embodiment of the present invention there are disclosed compounds represented by Formula I, or pharmaceutically acceptable salts, esters, or prodrugs thereof:

wherein

-   -   R is selected from the group consisting of:

 denotes a carbon-carbon single or double bond.

DETAILED DESCRIPTION OF THE INVENTION

A first embodiment of the invention is a compound represented by Formula I as described above, or a pharmaceutically acceptable salts, esters or prodrugs thereof, alone or in combination with a pharmaceutically acceptable carrier or excipient.

In one embodiment, is a compound represented by Formula II as described below, or a pharmaceutically acceptable salts, esters or prodrugs thereof, alone or in combination with a pharmaceutically acceptable carrier or excipient.

wherein R is as defined in the first embodiment.

In one embodiment, is a compound represented by Formula III as described below, or a pharmaceutically acceptable salts, esters or prodrugs thereof, alone or in combination with a pharmaceutically acceptable carrier or excipient.

wherein R is defined are as defined in the previous embodiment.

Representative compounds of the invention include, but are not limited to, the following compounds (Table 1) according to Formula II:

TABLE 1 II

Compound # R 1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

Further representative compounds of the invention include, but are not limited to, the following compounds (Table 2) according to Formula III:

TABLE 2 III

Compound # R 71

72

The present invention also features pharmaceutical compositions comprising a compound of the present invention, or a pharmaceutically acceptable salt, ester or prodrug thereof.

Compounds of the present invention can be administered as the sole active pharmaceutical agent, or used in combination with one or more agents to treat or prevent hepatitis C infections or the symptoms associated with HCV infection. Other agents to be administered in combination with a compound or combination of compounds of the invention include therapies for disease caused by HCV infection that suppresses HCV viral replication by direct or indirect mechanisms. These include agents such as host immune modulators (for example, interferon-alpha, pegylated interferon-alpha, interferon-beta, interferon-gamma, CpG oligonucleotides and the like), or antiviral compounds that inhibit host cellular functions such as inosine monophosphate dehydrogenase (for example, ribavirin and the like). Also included are cytokines that modulate immune function. Also included are vaccines comprising HCV antigens or antigen adjuvant combinations directed against HCV. Also included are agents that interact with host cellular components to block viral protein synthesis by inhibiting the internal ribosome entry site (IRES) initiated translation step of HCV viral replication or to block viral particle maturation and release with agents targeted toward the viroporin family of membrane proteins such as, for example, HCV P7 and the like. Other agents to be administered in combination with a compound of the present invention include any agent or combination of agents that inhibit the replication of HCV by targeting proteins of the viral genome involved in the viral replication. These agents include but are not limited to other inhibitors of HCV RNA dependent RNA polymerase such as, for example, nucleoside type polymerase inhibitors described in WO01 90121(A2), or U.S. Pat. No. 6,348,587B1 or WO0160315 or WO0132153 or non-nucleoside inhibitors such as, for example, benzimidazole polymerase inhibitors described in EP 1162196A 1 or WO0204425 or inhibitors of HCV protease such as, for example, peptidomimetic type inhibitors such as BILN2061 and the like or inhibitors of HCV helicase.

Other agents to be administered in combination with a compound of the present invention include any agent or combination of agents that inhibit the replication of other viruses for co-infected individuals. These agent include but are not limited to therapies for disease caused by hepatitis B (HBV) infection such as, for example, adefovir, lamivudine, and tenofovir or therapies for disease caused by human immunodeficiency virus (HIV) infection such as, for example, protease inhibitors: lopinavir, indinavir, nelfinavir, saquinavir, amprenavir, atazanavir, tipranavir, TMC-114, fosamprenavir; reverse transcriptase inhibitors: zidovudine, lamivudine, didanosine, stavudine, tenofovir, zalcitabine, abacavir, efavirenz, nevirapine, delavirdine, TMC-125; integrase inhibitors: L-870812, S-1360, or entry inhibitors: enfuvirtide (T-20), T-1249.

Accordingly, one aspect of the invention is directed to a method for treating or preventing an infection caused by an RNA-containing virus comprising co-administering to a patient in need of such treatment one or more agents selected from the group consisting of a host immune modulator and a second antiviral agent, or a combination thereof, with a therapeutically effective amount of a compound or combination of compounds of the invention, or a pharmaceutically acceptable salt, stereoisomer, tautomer, prodrug, salt of a prodrug, or combination thereof. Examples of the host immune modulator are, but not limited to, interferon-alpha, pegylated-interferon-alpha, interferon-beta, interferon-gamma, a cytokine, a vaccine, and a vaccine comprising an antigen and an adjuvant, and said second antiviral agent inhibits replication of HCV either by inhibiting host cellular functions associated with viral replication or by targeting proteins of the viral genome.

Further aspect of the invention is directed to a method of treating or preventing infection caused by an RNA-containing virus comprising co-administering to a patient in need of such treatment an agent or combination of agents that treat or alleviate symptoms of HCV infection including cirrhosis and inflammation of the liver, with a therapeutically effective amount of a compound or combination of compounds of the invention, or a pharmaceutically acceptable salt, stereoisomer, tautomer, prodrug, salt of a prodrug, or combination thereof. Yet another aspect of the invention provides a method of treating or preventing infection caused by an RNA-containing virus comprising co-administering to a patient in need of such treatment one or more agents that treat patients for disease caused by hepatitis B (HBV) infection, with a therapeutically effective amount of a compound or a combination of compounds of the invention, or a pharmaceutically acceptable salt, stereoisomer, tautomer, prodrug, salt of a prodrug, or combination thereof. An agent that treats patients for disease caused by hepatitis B (HBV) infection may be for example, but not limited thereto, L-deoxythymidine, adefovir, lamivudine or tenofovir, or any combination thereof. Example of the RNA-containing virus includes, but not limited to, hepatitis C virus (HCV).

Another aspect of the invention provides a method of treating or preventing infection caused by an RNA-containing virus comprising co-administering to a patient in need of such treatment one or more agents that treat patients for disease caused by human immunodeficiency virus (HIV) infection, with a therapeutically effective amount of a compound or a combination of compounds of the invention, or a pharmaceutically acceptable salt, stereoisomer, tautomer, prodrug, salt of a prodrug, or combination thereof. The agent that treats patients for disease caused by human immunodeficiency virus (HIV) infection may include, but is not limited thereto, lopinavir, indinavir, nelfmavir, saquinavir, amprenavir, atazanavir, tipranavir, TMC-114, fosamprenavir, zidovudine, lamivudine, didanosine, stavudine, tenofovir, zalcitabine, abacavir, efavirenz, nevirapine, delavirdine, TMC-125, L-870812, S-1360, enfuvirtide (T-20) or T-1249, or any combination thereof. Example of the RNA-containing virus includes, but not limited to, hepatitis C virus (HCV). In addition, the present invention provides the use of a compound or a combination of compounds of the invention, or a therapeutically acceptable salt form, stereoisomer, or tautomer, prodrug, salt of a prodrug, or combination thereof, and one or more agents selected from the group consisting of a host immune modulator and a second antiviral agent, or a combination thereof, to prepare a medicament for the treatment of an infection caused by an RNA-containing virus in a patient, particularly hepatitis C virus.

Examples of the host immune modulator are, but not limited to, interferon-alpha, pegylated-interferon-alpha, interferon-beta, interferon-gamma, a cytokine, a vaccine, and a vaccine comprising an antigen and an adjuvant, and said second antiviral agent inhibits replication of HCV either by inhibiting host cellular functions associated with viral replication or by targeting proteins of the viral genome.

When used in the above or other treatments, combination of compound or compounds of the invention, together with one or more agents as defined herein above, can be employed in pure form or, where such forms exist, in pharmaceutically acceptable salt form, prodrug, salt of a prodrug, or combination thereof. Alternatively, such combination of therapeutic agents can be administered as a pharmaceutical composition containing a therapeutically effective amount of the compound or combination of compounds of interest, or their pharmaceutically acceptable salt form, prodrugs, or salts of the prodrug, in combination with one or more agents as defined hereinabove, and a pharmaceutically acceptable carrier. Such pharmaceutical compositions can be used for inhibiting the replication of an RNA-containing virus, particularly Hepatitis C virus (HCV), by contacting said virus with said pharmaceutical composition. In addition, such compositions are useful for the treatment or prevention of an infection caused by an RNA-containing virus, particularly Hepatitis C virus (HCV).

Hence, further aspect of the invention is directed to a method of treating or preventing infection caused by an RNA-containing virus, particularly a hepatitis C virus (HCV), comprising administering to a patient in need of such treatment a pharmaceutical composition comprising a compound or combination of compounds of the invention or a pharmaceutically acceptable salt, stereoisomer, or tautomer, prodrug, salt of a prodrug, or combination thereof, one or more agents as defined hereinabove, and a pharmaceutically acceptable carrier.

When administered as a combination, the therapeutic agents can be formulated as separate compositions which are given at the same time or within a predetermined period of time, or the therapeutic agents can be given as a single unit dosage form.

Antiviral agents contemplated for use in such combination therapy include agents (compounds or biologicals) that are effective to inhibit the formation and/or replication of a virus in a mammal, including but not limited to agents that interfere with either host or viral mechanisms necessary for the formation and/or replication of a virus in a mammal. Such agents can be selected from another anti-HCV agent; an HIV inhibitor; an HAV inhibitor; and an HBV inhibitor.

Other anti-HCV agents include those agents that are effective for diminishing or preventing the progression of hepatitis C related symptoms or disease. Such agents include but are not limited to immunomodulatory agents, inhibitors of HCV NS3 protease, other inhibitors of HCV polymerase, inhibitors of another target in the HCV life cycle and other anti-HCV agents, including but not limited to ribavirin, amantadine, levovirin and viramidine.

Immunomodulatory agents include those agents (compounds or biologicals) that are effective to enhance or potentiate the immune system response in a mammal. Immunomodulatory agents include, but are not limited to, inosine monophosphate dehydrogenase inhibitors such as VX-497 (merimepodib, Vertex Pharmaceuticals), class I interferons, class II interferons, consensus interferons, asialo-interferons pegylated interferons and conjugated interferons, including but not limited to interferons conjugated with other proteins including but not limited to human albumin. Class I interferons are a group of interferons that all bind to receptor type I, including both naturally and synthetically produced class I interferons, while class II interferons all bind to receptor type II. Examples of class I interferons include, but are not limited to, [alpha]-, [beta]-, [delta]-, [omega]-, and [tau]-interferons, while examples of class II interferons include, but are not limited to, [gamma]-interferons.

Inhibitors of HCV NS3 protease include agents (compounds or biologicals) that are effective to inhibit the function of HCV NS3 protease in a mammal. Inhibitors of HCV NS3 protease include, but are not limited to, those compounds described in WO 99/07733, WO 99/07734, WO 00/09558, WO 00/09543, WO 00/59929, WO 03/064416, WO 03/064455, WO 03/064456, WO 2004/030670, WO 2004/037855, WO 2004/039833, WO 2004/101602, WO 2004/101605, WO 2004/103996, WO 2005/028501, WO 2005/070955, WO 2006/000085, WO 2006/007700 and WO 2006/007708 (all by Boehringer Ingelheim), WO 02/060926, WO 03/053349, WO03/099274, WO 03/099316, WO 2004/032827, WO 2004/043339, WO 2004/094452, WO 2005/046712, WO 2005/051410, WO 2005/054430 (all by BMS), WO 2004/072243, WO 2004/093798, WO 2004/113365, WO 2005/010029 (all by Enanta), WO 2005/037214 (Intermune) and WO 2005/051980 (Schering), and the candidates identified as VX-950, ITMN-191 and SCH 503034.

Inhibitors of HCV polymerase include agents (compounds or biologicals) that are effective to inhibit the function of an HCV polymerase. Such inhibitors include, but are not limited to, non-nucleoside and nucleoside inhibitors of HCV NS5B polymerase. Examples of inhibitors of HCV polymerase include but are not limited to those compounds described in: WO 02/04425, WO 03/007945, WO 03/010140, WO 03/010141, WO 2004/064925, WO 2004/065367, WO 2005/080388 and WO 2006/007693 (all by Boehringer Ingelheim), WO 2005/049622 (Japan Tobacco), WO 2005/014543 (Japan Tobacco), WO 2005/012288 (Genelabs), WO 2004/087714 (IRBM), WO 03/101993 (Neogenesis), WO 03/026587 (BMS), WO 03/000254 (Japan Tobacco), and WO 01/47883 (Japan Tobacco), and the clinical candidates XTL-2125, HCV 796, R-1626 and NM 283.

Inhibitors of another target in the HCV life cycle include agents (compounds or biologicals) that are effective to inhibit the formation and/or replication of HCV other than by inhibiting the function of the HCV NS3 protease. Such agents may interfere with either host or HCV viral mechanisms necessary for the formation and/or replication of HCV. Inhibitors of another target in the HCV life cycle include, but are not limited to, entry inhibitors, agents that inhibit a target selected from a helicase, a NS2/3 protease and an internal ribosome entry site (IRES) and agents that interfere with the function of other viral targets including but not limited to an NS5A protein and an NS4B protein.

It can occur that a patient may be co-infected with hepatitis C virus and one or more other viruses, including but not limited to human immunodeficiency virus (HIV), hepatitis A virus (HAV) and hepatitis B virus (HBV). Thus also contemplated is combination therapy to treat such co-infections by co-administering a compound according to the present invention with at least one of an HIV inhibitor, an HAV inhibitor and an HBV inhibitor.

According to yet another embodiment, the pharmaceutical compositions of the present invention may further comprise inhibitor(s) of other targets in the HCV life cycle, including, but not limited to, helicase, polymerase, metalloprotease, and internal ribosome entry site (IRES).

According to another embodiment, the pharmaceutical compositions of the present invention may further comprise another anti-viral, anti-bacterial, anti-fungal or anti-cancer agent, or an immune modulator, or another therapeutic agent.

According to still another embodiment, the present invention includes methods of treating viral infection such as, but not limited to, hepatitis C infections in a subject in need of such treatment by administering to said subject an effective amount of a compound of the present invention or a pharmaceutically acceptable salt, ester, or prodrug thereof.

According to a further embodiment, the present invention includes methods of treating hepatitis C infections in a subject in need of such treatment by administering to said subject an anti-HCV virally effective amount or an inhibitory amount of a pharmaceutical composition of the present invention.

An additional embodiment of the present invention includes methods of treating biological samples by contacting the biological samples with the compounds of the present invention.

Yet a further aspect of the present invention is a process of making any of the compounds delineated herein employing any of the synthetic means delineated herein.

Definitions

Listed below are definitions of various terms used to describe this invention. These definitions apply to the terms as they are used throughout this specification and claims, unless otherwise limited in specific instances, either individually or as part of a larger group.

The term “viral infection” refers to the introduction of a virus into cells or tissues, e.g., hepatitis C virus (HCV). In general, the introduction of a virus is also associated with replication. Viral infection may be determined by measuring virus antibody titer in samples of a biological fluid, such as blood, using, e.g., enzyme immunoassay. Other suitable diagnostic methods include molecular based techniques, such as RT-PCR, direct hybrid capture assay, nucleic acid sequence based amplification, and the like. A virus may infect an organ, e.g., liver, and cause disease, e.g., hepatitis, cirrhosis, chronic liver disease and hepatocellular carcinoma.

The term “anti-cancer agent” refers to a compound or drug capable of preventing or inhibiting the advancement of cancer. Examples of such agents include cis-platin, actinomycin D, doxorubicin, vincristine, vinblastine, etoposide, amsacrine, mitoxantrone, tenipaside, taxol, colchicine, cyclosporin A, phenothiazines or thioxantheres.

The term “anti-fungal agent” shall used to describe a compound which may be used to treat a fungus infection other than 3-AP, 3-AMP or prodrugs of 3-AP and 3-AMP according to the present invention. Anti-fungal agents according to the present invention include, for example, terbinafine, fluconazole, itraconazole, posaconazole, clotrimazole, griseofulvin, nystatin, tolnaftate, caspofungin, amphotericin B, liposomal amphotericin B, and amphotericin B lipid complex.

The term “antibacterial agent” refers to both naturally occurring antibiotics produced by microorganisms to suppress the growth of other microorganisms, and agents synthesized or modified in the laboratory which have either bactericidal or bacteriostatic activity, e.g., β-lactam antibacterial agents, glycopeptides, macrolides, quinolones, tetracyclines, and aminoglycosides. In general, if an antibacterial agent is bacteriostatic, it means that the agent essentially stops bacterial cell growth (but does not kill the bacteria); if the agent is bacteriocidal, it means that the agent kills the bacterial cells (and may stop growth before killing the bacteria).

The term “immune modulator” refers to any substance meant to alter the working of the humoral or cellular immune system of a subject. Such immune modulators include inhibitors of mast cell-mediated inflammation, interferons, interleukins, prostaglandins, steroids, cortico-steroids, colony-stimulating factors, chemotactic factors, etc.

The compounds described herein contain one or more asymmetric centers and thus give rise to enantiomers, diastereomers, and other stereoisomeric forms that may be defined, in terms of absolute stereochemistry, as (R)- or (S)-, or as (D)- or (L)- for amino acids. The present invention is meant to include all such possible isomers, as well as their racemic and optically pure forms. Optical isomers may be prepared from their respective optically active precursors by the procedures described above, or by resolving the racemic mixtures. The resolution can be carried out in the presence of a resolving agent, by chromatography or by repeated crystallization or by some combination of these techniques, which are known to those skilled in the art. Further details regarding resolutions can be found in Jacques, et al., Enantiomers, Racemates, and Resolutions (John Wiley & Sons, 1981). When the compounds described herein contain olefinic double bonds or other centers of geometric asymmetry, and unless specified otherwise, it is intended that the compounds include both E and Z geometric isomers. Likewise, all tautomeric forms are also intended to be included. The configuration of any carbon-carbon double bond appearing herein is selected for convenience only and is not intended to designate a particular configuration unless the text so states; thus a carbon-carbon double bond depicted arbitrarily herein as trans may be cis, trans, or a mixture of the two in any proportion.

The term “subject” as used herein refers to a mammal. A subject therefore refers to, for example, dogs, cats, horses, cows, pigs, guinea pigs, and the like. Preferably the subject is a human. When the subject is a human, the subject may be referred to herein as a patient.

As used herein, the term “pharmaceutically acceptable salt” refers to those salts of the compounds formed by the process of the present invention which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of humans and lower animals without undue toxicity, irritation, allergic response and the like, and are commensurate with a reasonable benefit/risk ratio. Pharmaceutically acceptable salts are well known in the art.

The term “amino protecting group,” as used herein, refers to a labile chemical moiety which is known in the art to protect an amino group against undesired reactions during synthetic procedures. After said synthetic procedure(s) the amino protecting group as described herein may be selectively removed. Amino protecting groups as known in the are described generally in T. H. Greene and P. G. M. Wuts, Protective Groups in Organic Synthesis, 3rd edition, John Wiley & Sons, New York (1999). Examples of amino protecting groups include, but are not limited to, t-butoxycarbonyl, 9-fluorenylmethoxycarbonyl, benzyloxycarbonyl, and the like.

As used herein, the term “pharmaceutically acceptable ester” refers to esters of the compounds formed by the process of the present invention which hydrolyze in vivo and include those that break down readily in the human body to leave the parent compound or a salt thereof. Suitable ester groups include, for example, those derived from pharmaceutically acceptable aliphatic carboxylic acids, particularly alkanoic, alkenoic, cycloalkanoic and alkanedioic acids, in which each alkyl or alkenyl moiety advantageously has not more than 6 carbon atoms. Examples of particular esters include, but are not limited to, formates, acetates, propionates, butyrates, acrylates and ethylsuccinates.

The term “pharmaceutically acceptable prodrugs” as used herein refers to those prodrugs of the compounds formed by the process of the present invention which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of humans and lower animals with undue toxicity, irritation, allergic response, and the like, commensurate with a reasonable benefit/risk ratio, and effective for their intended use, as well as the zwitterionic forms, where possible, of the compounds of the present invention. “Prodrug”, as used herein means a compound, which is convertible in vivo by metabolic means (e.g. by hydrolysis) to afford any compound delineated by the formulae of the instant invention. Various forms of prodrugs are known in the art, for example, as discussed in Bundgaard, (ed.), Design of Prodrugs, Elsevier (1985); Widder, et al. (ed.), Methods in Enzymology, vol. 4, Academic Press (1985); Krogsgaard-Larsen, et al., (ed). “Design and Application of Prodrugs, Textbook of Drug Design and Development, Chapter 5, 113-191 (1991); Bundgaard, et al., Journal of Drug Deliver Reviews, 8:1-38 (1992); Bundgaard, J. of Pharmaceutical Sciences, 77:285 et seq. (1988); Higuchi and Stella (eds.) Prodrugs as Novel Drug Delivery Systems, American Chemical Society (1975); and Bernard Testa & Joachim Mayer, “Hydrolysis In Drug And Prodrug Metabolism: Chemistry, Biochemistry And Enzymology,” John Wiley and Sons, Ltd. (2002).

The term “aprotic solvent,” as used herein, refers to a solvent that is relatively inert to proton activity, i.e., not acting as a proton-donor. Examples include, but are not limited to, hydrocarbons, such as hexane and toluene, for example, halogenated hydrocarbons, such as, for example, methylene chloride, ethylene chloride, chloroform, and the like, heterocyclic compounds, such as, for example, tetrahydrofuran and N-methylpyrrolidinone, and ethers such as diethyl ether, bis-methoxymethyl ether. Such solvents are well known to those skilled in the art, and individual solvents or mixtures thereof may be preferred for specific compounds and reaction conditions, depending upon such factors as the solubility of reagents, reactivity of reagents and preferred temperature ranges, for example. Further discussions of aprotic solvents may be found in organic chemistry textbooks or in specialized monographs, for example: Organic Solvents Physical Properties and Methods of Purification, 4th ed., edited by John A. Riddick et al., Vol. II, in the Techniques of Chemistry Series, John Wiley & Sons, NY, 1986.

The terms “protogenic organic solvent” or “protic solvent” as used herein, refer to a solvent that tends to provide protons, such as an alcohol, for example, methanol, ethanol, propanol, isopropanol, butanol, t-butanol, and the like. Such solvents are well known to those skilled in the art, and individual solvents or mixtures thereof may be preferred for specific compounds and reaction conditions, depending upon such factors as the solubility of reagents, reactivity of reagents and preferred temperature ranges, for example. Further discussions of protogenic solvents may be found in organic chemistry textbooks or in specialized monographs, for example: Organic Solvents Physical Properties and Methods of Purification, 4th ed., edited by John A. Riddick et al., Vol. II, in the Techniques of Chemistry Series, John Wiley & Sons, NY, 1986.

The synthesized compounds can be separated from a reaction mixture and further purified by a method such as column chromatography, high pressure liquid chromatography, or recrystallization. Additionally, the various synthetic steps may be performed in an alternate sequence or order to give the desired compounds. In addition, the solvents, temperatures, reaction durations, etc. delineated herein are for purposes of illustration only and variation of the reaction conditions can produce the desired bridged macrocyclic products of the present invention. Synthetic chemistry transformations and protecting group methodologies (protection and deprotection) useful in synthesizing the compounds described herein include, for example, those described in R. Larock, Comprehensive Organic Transformations, VCH Publishers (1989); T. W. Greene and P. G. M. Wuts, Protective Groups in Organic Synthesis, 2d. Ed., John Wiley and Sons (1991); L. Fieser and M. Fieser, Fieser and Fieser's Reagents for Organic Synthesis, John Wiley and Sons (1994); and L. Paquette, ed., Encyclopedia of Reagents for Organic Synthesis, John Wiley and Sons (1995).

The compounds of this invention may be modified by appending various functionalities via synthetic means delineated herein to enhance selective biological properties. Such modifications include those which increase biological penetration into a given biological system (e.g., blood, lymphatic system, central nervous system), increase oral availability, increase solubility to allow administration by injection, alter metabolism and alter rate of excretion.

Pharmaceutical Compositions

The pharmaceutical compositions of the present invention comprise a therapeutically effective amount of a compound of the present invention formulated together with one or more pharmaceutically acceptable carriers. As used herein, the term “pharmaceutically acceptable carrier” means a non-toxic, inert solid, semi-solid or liquid filler, diluent, encapsulating material or formulation auxiliary of any type. Some examples of materials which can serve as pharmaceutically acceptable carriers are sugars such as lactose, glucose and sucrose; starches such as corn starch and potato starch; cellulose and its derivatives such as sodium carboxymethyl cellulose, ethyl cellulose and cellulose acetate; powdered tragacanth; malt; gelatin; talc; excipients such as cocoa butter and suppository waxes; oils such as peanut oil, cottonseed oil; safflower oil; sesame oil; olive oil; corn oil and soybean oil; glycols; such a propylene glycol; esters such as ethyl oleate and ethyl laurate; agar; buffering agents such as magnesium hydroxide and aluminum hydroxide; alginic acid; pyrogen-free water; isotonic saline; Ringer's solution; ethyl alcohol, and phosphate buffer solutions, as well as other non-toxic compatible lubricants such as sodium lauryl sulfate and magnesium stearate, as well as coloring agents, releasing agents, coating agents, sweetening, flavoring and perfuming agents, preservatives and antioxidants can also be present in the composition, according to the judgment of the formulator. The pharmaceutical compositions of this invention can be administered to humans and other animals orally, rectally, parenterally, intracisternally, intravaginally, intraperitoneally, topically (as by powders, ointments, or drops), buccally, or as an oral or nasal spray.

The pharmaceutical compositions of this invention may be administered orally, parenterally, by inhalation spray, topically, rectally, nasally, buccally, vaginally or via an implanted reservoir, preferably by oral administration or administration by injection. The pharmaceutical compositions of this invention may contain any conventional non-toxic pharmaceutically-acceptable carriers, adjuvants or vehicles. In some cases, the pH of the formulation may be adjusted with pharmaceutically acceptable acids, bases or buffers to enhance the stability of the formulated compound or its delivery form. The term parenteral as used herein includes subcutaneous, intracutaneous, intravenous, intramuscular, intraarticular, intraarterial, intrasynovial, intrasternal, intrathecal, intralesional and intracranial injection or infusion techniques.

Liquid dosage forms for oral administration include pharmaceutically acceptable emulsions, microemulsions, solutions, suspensions, syrups and elixirs. In addition to the active compounds, the liquid dosage forms may contain inert diluents commonly used in the art such as, for example, water or other solvents, solubilizing agents and emulsifiers such as ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethyl acetate, benzyl alcohol, benzyl benzoate, propylene glycol, 1,3-butylene glycol, dimethylformamide, oils (in particular, cottonseed, groundnut, corn, germ, olive, castor, and sesame oils), glycerol, tetrahydrofurfuryl alcohol, polyethylene glycols and fatty acid esters of sorbitan, and mixtures thereof. Besides inert diluents, the oral compositions can also include adjuvants such as wetting agents, emulsifying and suspending agents, sweetening, flavoring, and perfuming agents.

Injectable preparations, for example, sterile injectable aqueous or oleaginous suspensions may be formulated according to the known art using suitable dispersing or wetting agents and suspending agents. The sterile injectable preparation may also be a sterile injectable solution, suspension or emulsion in a nontoxic parenterally acceptable diluent or solvent, for example, as a solution in 1,3-butanediol. Among the acceptable vehicles and solvents that may be employed are water, Ringer's solution, U.S.P. and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium. For this purpose any bland fixed oil can be employed including synthetic mono- or diglycerides. In addition, fatty acids such as oleic acid are used in the preparation of injectables.

The injectable formulations can be sterilized, for example, by filtration through a bacterial-retaining filter, or by incorporating sterilizing agents in the form of sterile solid compositions which can be dissolved or dispersed in sterile water or other sterile injectable medium prior to use.

In order to prolong the effect of a drug, it is often desirable to slow the absorption of the drug from subcutaneous or intramuscular injection. This may be accomplished by the use of a liquid suspension of crystalline or amorphous material with poor water solubility. The rate of absorption of the drug then depends upon its rate of dissolution, which, in turn, may depend upon crystal size and crystalline form. Alternatively, delayed absorption of a parenterally administered drug form is accomplished by dissolving or suspending the drug in an oil vehicle. Injectable depot forms are made by forming microencapsule matrices of the drug in biodegradable polymers such as polylactide-polyglycolide. Depending upon the ratio of drug to polymer and the nature of the particular polymer employed, the rate of drug release can be controlled. Examples of other biodegradable polymers include poly(orthoesters) and poly(anhydrides). Depot injectable formulations are also prepared by entrapping the drug in liposomes or microemulsions which are compatible with body tissues.

Compositions for rectal or vaginal administration are preferably suppositories which can be prepared by mixing the compounds of this invention with suitable non-irritating excipients or carriers such as cocoa butter, polyethylene glycol or a suppository wax which are solid at ambient temperature but liquid at body temperature and therefore melt in the rectum or vaginal cavity and release the active compound.

Solid dosage forms for oral administration include capsules, tablets, pills, powders, and granules. In such solid dosage forms, the active compound is mixed with at least one inert, pharmaceutically acceptable excipient or carrier such as sodium citrate or dicalcium phosphate and/or: a) fillers or extenders such as starches, lactose, sucrose, glucose, mannitol, and silicic acid, b) binders such as, for example, carboxymethylcellulose, alginates, gelatin, polyvinylpyrrolidinone, sucrose, and acacia, c) humectants such as glycerol, d) disintegrating agents such as agar-agar, calcium carbonate, potato or tapioca starch, alginic acid, certain silicates, and sodium carbonate, e) solution retarding agents such as paraffin, f) absorption accelerators such as quaternary ammonium compounds, g) wetting agents such as, for example, cetyl alcohol and glycerol monostearate, h) absorbents such as kaolin and bentonite clay, and i) lubricants such as talc, calcium stearate, magnesium stearate, solid polyethylene glycols, sodium lauryl sulfate, and mixtures thereof. In the case of capsules, tablets and pills, the dosage form may also comprise buffering agents.

Solid compositions of a similar type may also be employed as fillers in soft and hard-filled gelatin capsules using such excipients as lactose or milk sugar as well as high molecular weight polyethylene glycols and the like.

The active compounds can also be in micro-encapsulated form with one or more excipients as noted above. The solid dosage forms of tablets, dragees, capsules, pills, and granules can be prepared with coatings and shells such as enteric coatings, release controlling coatings and other coatings well known in the pharmaceutical formulating art. In such solid dosage forms the active compound may be admixed with at least one inert diluent such as sucrose, lactose or starch. Such dosage forms may also comprise, as is normal practice, additional substances other than inert diluents, e.g., tableting lubricants and other tableting aids such a magnesium stearate and microcrystalline cellulose. In the case of capsules, tablets and pills, the dosage forms may also comprise buffering agents. They may optionally contain opacifying agents and can also be of a composition that they release the active ingredient(s) only, or preferentially, in a certain part of the intestinal tract, optionally, in a delayed manner. Examples of embedding compositions which can be used include polymeric substances and waxes.

Dosage forms for topical or transdermal administration of a compound of this invention include ointments, pastes, creams, lotions, gels, powders, solutions, sprays, inhalants or patches. The active component is admixed under sterile conditions with a pharmaceutically acceptable carrier and any needed preservatives or buffers as may be required. Ophthalmic formulation, ear drops, eye ointments, powders and solutions are also contemplated as being within the scope of this invention.

The ointments, pastes, creams and gels may contain, in addition to an active compound of this invention, excipients such as animal and vegetable fats, oils, waxes, paraffins, starch, tragacanth, cellulose derivatives, polyethylene glycols, silicones, bentonites, silicic acid, talc and zinc oxide, or mixtures thereof.

Powders and sprays can contain, in addition to the compounds of this invention, excipients such as lactose, talc, silicic acid, aluminum hydroxide, calcium silicates and polyamide powder, or mixtures of these substances. Sprays can additionally contain customary propellants such as chlorofluorohydrocarbons.

Transdermal patches have the added advantage of providing controlled delivery of a compound to the body. Such dosage forms can be made by dissolving or dispensing the compound in the proper medium. Absorption enhancers can also be used to increase the flux of the compound across the skin. The rate can be controlled by either providing a rate controlling membrane or by dispersing the compound in a polymer matrix or gel.

Antiviral Activity

An inhibitory amount or dose of the compounds of the present invention may range from about 0.01 mg/Kg to about 500 mg/Kg, alternatively from about 1 to about 50 mg/Kg. Inhibitory amounts or doses will also vary depending on route of administration, as well as the possibility of co-usage with other agents.

According to the methods of treatment of the present invention, viral infections are treated or prevented in a subject such as a human or lower mammal by administering to the subject an anti-hepatitis C virally effective amount or an inhibitory amount of a compound of the present invention, in such amounts and for such time as is necessary to achieve the desired result. An additional method of the present invention is the treatment of biological samples with an inhibitory amount of a compound of composition of the present invention in such amounts and for such time as is necessary to achieve the desired result.

The term “anti-hepatitis C virally effective amount” of a compound of the invention, as used herein, mean a sufficient amount of the compound so as to decrease the viral load in a biological sample or in a subject (e.g., resulting in at least 10%, preferably at least 50%, more preferably at least 80%, and most preferably at least 90% or 95%, reduction in viral load). As well understood in the medical arts, an anti-hepatitis C virally effective amount of a compound of this invention will be at a reasonable benefit/risk ratio applicable to any medical treatment.

The term “inhibitory amount” of a compound of the present invention means a sufficient amount to decrease the hepatitis C viral load in a biological sample or a subject (e.g., resulting in at least 10%, preferably at least 50%, more preferably at least 80%, and most preferably at least 90% or 95%, reduction in viral load). It is understood that when said inhibitory amount of a compound of the present invention is administered to a subject it will be at a reasonable benefit/risk ratio applicable to any medical treatment as determined by a physician. The term “biological sample(s),” as used herein, means a substance of biological origin intended for administration to a subject. Examples of biological samples include, but are not limited to, blood and components thereof such as plasma, platelets, subpopulations of blood cells and the like; organs such as kidney, liver, heart, lung, and the like; sperm and ova; bone marrow and components thereof, or stem cells. Thus, another embodiment of the present invention is a method of treating a biological sample by contacting said biological sample with an inhibitory amount of a compound or pharmaceutical composition of the present invention.

Upon improvement of a subject's condition, a maintenance dose of a compound, composition or combination of this invention may be administered, if necessary. Subsequently, the dosage or frequency of administration, or both, may be reduced, as a function of the symptoms, to a level at which the improved condition is retained when the symptoms have been alleviated to the desired level, treatment should cease. The subject may, however, require intermittent treatment on a long-term basis upon any recurrence of disease symptoms.

It will be understood, however, that the total daily usage of the compounds and compositions of the present invention will be decided by the attending physician within the scope of sound medical judgment. The specific inhibitory dose for any particular patient will depend upon a variety of factors including the disorder being treated and the severity of the disorder; the activity of the specific compound employed; the specific composition employed; the age, body weight, general health, sex and diet of the patient; the time of administration, route of administration, and rate of excretion of the specific compound employed; the duration of the treatment; drugs used in combination or coincidental with the specific compound employed; and like factors well known in the medical arts.

The total daily inhibitory dose of the compounds of this invention administered to a subject in single or in divided doses can be in amounts, for example, from 0.01 to 50 mg/kg body weight or more usually from 0.1 to 25 mg/kg body weight. Single dose compositions may contain such amounts or submultiples thereof to make up the daily dose. In general, treatment regimens according to the present invention comprise administration to a patient in need of such treatment from about 10 mg to about 1000 mg of the compound(s) of this invention per day in single or multiple doses.

Unless otherwise defined, all technical and scientific terms used herein are accorded the meaning commonly known to one with ordinary skill in the art. All publications, patents, published patent applications, and other references mentioned herein are hereby incorporated by reference in their entirety.

ABBREVIATIONS

Abbreviations which have been used in the descriptions of the schemes and the examples that follow are:

-   -   ACN for acetonitrile;     -   BME for 2-mercaptoethanol;     -   BOP for benzotriazol-1-yloxy-tris(dimethylamino)phosphonium         hexafluorophosphate;     -   COD for cyclooctadiene;     -   DAST for diethylaminosulfur trifluoride;     -   DABCYL for         6-(N-4′-carboxy-4-(dimethylamino)azobenzene)-aminohexyl-1-O-(2-cyanoethyl)-(N,N-diisopropyl)-phosphoramidite;     -   DCM for dichloromethane;     -   DIAD for diisopropyl azodicarboxylate;     -   DIBAL-H for diisobutylaluminum hydride;     -   DIEA for diisopropyl ethylamine;     -   DMAP for N,N-dimethylaminopyridine;     -   DME for ethylene glycol dimethyl ether;     -   DMEM for Dulbecco's Modified Eagles Media;     -   DMF for N,N-dimethyl formamide;     -   DMSO for dimethylsulfoxide;     -   EDANS for 5-(2-Amino-ethylamino)-naphthalene-1-sulfonic acid;     -   EDCI or EDC for 1-(3-diethylaminopropyl)-3-ethylcarbodiimide         hydrochloride;     -   EtOAc for ethyl acetate;     -   HATU for 0         (7-Azabenzotriazole-1-yl)-N,N,N′,N′-tetramethyluronium         hexafluorophosphate;     -   Hoveyda's Cat. for         Dichloro(o-isopropoxyphenylmethylene)(tricyclohexylphosphine)ruthenium(II);     -   KHMDS is potassium bis(trimethylsilyl) amide;     -   Ms for mesyl;     -   NMM for N-4-methylmorpholine;     -   PyBrOP for Bromo-tri-pyrrolidino-phosphonium         hexafluorophosphate;     -   Ph for phenyl;     -   RCM for ring-closing metathesis;     -   RT for reverse transcription;     -   RT-PCR for reverse transcription-polymerase chain reaction;     -   TBAF for tetrabutylammonium fluoride;     -   TEA for triethyl amine;     -   TFA for trifluoroacetic acid;     -   THF for tetrahydrofuran;     -   TLC for thin layer chromatography;     -   TPP or PPh₃ for triphenylphosphine;     -   tBOC or Boc for tert-butyloxy carbonyl; and     -   Xantphos for         4,5-Bis-diphenylphosphanyl-9,9-dimethyl-9H-xanthene.

Synthetic Methods

The compounds and processes of the present invention will be better understood in connection with the following synthetic schemes that illustrate the methods by which the compounds of the invention may be prepared.

All of the oximyl analogs were prepared from the common intermediate 1-6. The synthesis of compound 1-6 is outlined in Scheme 1. Deprotection of commercially available Boc-hydroxyproline 1-1 with HCl in dioxane followed by coupling with acid 1-2 using HATU, afforded intermediate 1-3. Other amino acid derivatives containing a terminal alkene may be used in place of 1-2 in order to generate varied macrocyclic structures (for further details see WO/0059929). Hydrolysis of 1-3 with LiOH followed by subsequent peptide coupling with cyclopropyl-containing amine 1-4 yielded tri-peptide 1-5. Finally, ring-closing metathesis with a ruthenium-based catalyst such as dichloro(o-isopropoxyphenylmethylene)(tricyclohexylphosphine)ruthenium(II) gave the desired key intermediate 1-6 (for further details on ring closing metathesis see recent reviews: Grubbs et al., Acc. Chem. Res., 1995, 28, 446; Shrock et al., Tetrahedron 1999, 55, 8141; Furstner, A. Angew. Chem. Int. Ed. 2000, 39, 3012; Trnka et al., Acc. Chem. Res. 2001, 34, 18; and Hoveyda et al., Chem. Eur. J. 2001, 7, 945).

The analogs of the present invention were prepared via several different synthetic routes. The simplest method, shown in Scheme 2, is to condense commercially available hydroxyphthalimide using Mitsunobu conditions followed by deprotection of the phthalimide moiety with ammonia or hydrazine to provide hydroxy amine (2-2). For further details on the Mitsunobu reaction, see O. Mitsunobu, Synthesis 1981, 1-28; D. L. Hughes, Org. React. 29, 1-162 (1983); D. L. Hughes, Organic Preparations and Procedures Int. 28, 127-164 (1996); and J. A. Dodge, S. A. Jones, Recent Res. Dev. Org. Chem. 1, 273-283 (1997). Alternatively, intermediate (2-2) can also be made by converting hydroxy intermediate Ig to a suitable leaving group such as, but not limited to OMs, OTs, OTf, bromide, or iodide; followed with the deprotection of the phthalimide moiety with ammonia or hydrazine. Oximes (2-3) can be prepared by treating hydroxy amine with 9H-fluoren-9-one optionally in the presence of an acid. Subsequent removal of the acid protecting group furnishes compounds of formula (2-4).

A thorough discussion of solvents and conditions for protecting the acid group can be found in T. W. Greene and P. G. M. Wuts, Protective Groups in Organic Synthesis, 3^(rd) ed., John Wiley & Son, Inc, 1999.

The Scheme 3 describes the alternative methods to synthesize formula (3-2). The intermediates (3-1) can be made directly through Ig and oximes using Mitsunobu conditions. Or, intermediate (3-1) can also be made through SN2 replacement of activated hydroxyl group by converting hydroxy intermediate Ig to a suitable leaving group such as, but not limited to OMs, OTs, OTf, bromide, or iodide. Subsequent removal of the acid protecting group furnishes compounds of formula (3-2).

Scheme 4 illustrates the modification of the N-terminal and C-terminal of the macrocycle. Deprotection of the Boc moiety with an acid, such as, but not limited to hydrochloric acid yields compounds of formula (4-2). The amino moiety of formula (4-2) can be alkylated or acylated with appropriate alkyl halide or acyl groups to give compounds of formula (4-3). Compounds of formula (4-3) can be hydrolyzed with base such as lithium hydroxide to free up the acid moiety of formula (4-4). Subsequent activation of the acid moiety followed by treatment with appropriate acyl or sulfonyl groups to provide compounds of formula (4-5).

EXAMPLES

The compounds and processes of the present invention will be better understood in connection with the following examples, which are intended as an illustration only and not to limit the scope of the invention. Various changes and modifications to the disclosed embodiments will be apparent to those skilled in the art and such changes and modifications including, without limitation, those relating to the chemical structures, substituents, derivatives, formulations and/or methods of the invention may be made without departing from the spirit of the invention and the scope of the appended claims.

Example 1 to Example 72 can be made following similar procedures described in copending application Ser. No. 11/759,080, which is incorporated herein by reference.

Example 1

Compound of Formula B, wherein R=

(compound 31).

To a solution of compound A (25.0 mg, 0.039 mmol), 5-methylisoxazole-3-carboxylic acid (5.4 mg, 0.043 mmol) and HATU (16.2 mg, 0.043 mmol) in DMF (0.5 mL) was added diisopropylethylamine (15.0 mg, 0.116 mmol). The reaction mixture was stirred at 25° C. for 16 h and then evaporated under a positive flow of nitrogen. The residue was purified by reverse phase chromatography to give the desired product (20.8 mg, 71% yield).

MS (ESI): m/z=755.1 [M+H].

Example 2

Compound of formula B, wherein R=

(compound 32).

The title compound was prepared using the procedure from Example 1, substituting 1-methyl-1H-pyrazole-3-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (75% yield).

MS (ESI): m/z=754.1 [M+H].

Example 3

Compound of formula B, wherein R=

(compound 62).

The title compound was prepared using the procedure from Example 1, substituting 1,5-dimethyl-1H-pyrazole-4-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (54% yield).

MS (ESI): m/z=768.1 [M+H].

Example 4

Compound of formula B, wherein R=

(compound 2).

The title compound was prepared using the procedure from Example 1, substituting isonicotinic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (39% yield).

MS (ESI): m/z=751.1 [M+H].

Example 5

Compound of formula B, wherein R=

(compound 3).

The title compound was prepared using the procedure from Example 1, substituting thiophene-3-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (45% yield).

MS (ESI): m/z=756.1 [M+H].

Example 6

Compound of formula B, wherein R=

(compound 4).

The title compound was prepared using the procedure from Example 1, substituting 1-methyl-1H-pyrrole-2-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (30% yield).

MS (ESI): m/z=751.1 [M−H].

Example 7

Compound of formula B, wherein R=

(compound 5).

The title compound was prepared using the procedure from Example 1, substituting thiazole-4-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (55% yield).

MS (ESI): m/z=757.1 [M+H].

Example 8

Compound of formula B, wherein R=

(compound 6).

The title compound was prepared using the procedure from Example 1, substituting furan-3-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (42% yield).

MS (ESI): m/z=740.1 [M+H].

Example 9

Compound of formula B, wherein R=

(compound 7).

The title compound was prepared using the procedure from Example 1, substituting 6-methylnicotinic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (72% yield).

MS (ESI): m/z=765.2 [M+H].

Example 10

Compound of formula B, wherein R=

(compound 9).

The title compound was prepared using the procedure from Example 1, substituting 2,4-dimethylthiazole-5-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (44% yield).

MS (ESI): m/z=782.9 [M−H].

Example 11

Compound of formula B, wherein R=

(compound 14).

The title compound was prepared using the procedure from Example 1, substituting 1H-pyrazole-4-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (48% yield).

MS (ESI): m/z=740.1 [M+H].

Example 12

Compound of formula B, wherein R=

(compound 15).

The title compound was prepared using the procedure from Example 1, substituting pyridazine-4-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (34% yield).

MS (ESI): m/z=752.2 [M+H].

Example 13

Compound of formula B, wherein R=

(compound 16).

The title compound was prepared using the procedure from Example 1, substituting 5-methylpyrazine-2-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (76% yield).

MS (ESI): m/z=766.1 [M+H].

Example 14

Compound of formula B, wherein R=

(compound 17).

The title compound was prepared using the procedure from Example 1, substituting 3-methylthiophene-2-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (32% yield).

MS (ESI): m/z=770.1 [M+H].

Example 15

Compound of formula B, wherein R=

(compound 18).

The title compound was prepared using the procedure from Example 1, substituting 3-chlorothiophene-2-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (38% yield).

MS (ESI): m/z=790.0 [M+H].

Example 16

Compound of formula B, wherein R=

(compound 25).

The title compound was prepared using the procedure from Example 1, substituting 4-fluorobenzoic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (91% yield).

MS (ESI): m/z=768.1 [M+H].

Example 17

Compound of formula B, wherein R=

(compound 26).

The title compound was prepared using the procedure from Example 1, substituting 3-fluorobenzoic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (69% yield).

MS (ESI): m/z=768.0 [M+H].

Example 18

Compound of formula B, wherein R=

(compound 27).

The title compound was prepared using the procedure from Example 1, substituting 2-fluorobenzoic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (62% yield).

MS (ESI): m/z=768.1 [M+H].

Example 19

Compound of formula B, wherein R=

(compound 29).

The title compound was prepared using the procedure from Example 1, substituting 2-(pyridin-4-yl)acetic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (75% yield).

MS (ESI): m/z=765.1 [M+H].

Example 20

Compound of formula B, wherein R=

(compound 30).

The title compound was prepared using the procedure from Example 1, substituting 2-(pyridin-3-yl)acetic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (84% yield).

MS (ESI): m/z=765.1 [M+H].

Example 21

Compound of formula B, wherein R=

(compound 34).

The title compound was prepared using the procedure from Example 1, substituting 3-methylisoxazole-4-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (79% yield).

MS (ESI): m/z=755.2 [M+H].

Example 22

Compound of formula B, wherein R=

(compound 35).

The title compound was prepared using the procedure from Example 1, substituting 1-methyl-1H-imidazole-5-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (62% yield).

MS (ESI): m/z=754.2 [M+H].

Example 23

Compound of formula B, wherein R=

(compound 36).

The title compound was prepared using the procedure from Example 1, substituting 1,3,5-trimethyl-1H-pyrazole-4-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (77% yield).

MS (ESI): m/z=782.1 [M+H].

Example 24

Compound of formula B, wherein R=

(compound 37).

The title compound was prepared using the procedure from Example 1, substituting 3,5-dimethylisoxazole-4-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (76% yield).

MS (ESI): m/z=769.1 [M+H].

Example 25

Compound of formula B, wherein R=

(compound 38).

The title compound was prepared using the procedure from Example 1, substituting 2-fluoronicotinic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (72% yield).

MS (ESI): m/z=769.1 [M+H].

Example 26

Compound of Formula B, wherein R=

(compound 39).

The title compound was prepared using the procedure from Example 1, substituting 6-methylpicolinic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (72% yield).

MS (ESI): m/z=765.1 [M+H].

Example 27

Compound of formula B, wherein R=

(compound 40).

The title compound was prepared using the procedure from Example 1, substituting 5-methyl-1H-pyrazole-3-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (64% yield).

MS (ESI): m/z=754.2 [M+H].

Example 28

Compound of formula B, wherein R=

(compound 41).

The title compound was prepared using the procedure from Example 1, substituting 1,3-dimethyl-1H-pyrazole-5-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (73% yield).

MS (ESI): m/z=768.1 [M+H].

Example 29

Compound of formula B, wherein R=

(compound 42).

The title compound was prepared using the procedure from Example 1, substituting 1,5-dimethyl-1H-pyrazole-3-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (75% yield).

MS (ESI): m/z=768.1 [M+H].

Example 30

Compound of formula B, wherein R=

(compound 44).

The title compound was prepared using the procedure from Example 1, substituting 3,5-dimethyl-1H-pyrazole-4-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (55% yield).

MS (ESI): m/z=768.1 [M+H].

Example 31

Compound of formula B, wherein R=

(compound 45).

The title compound was prepared using the procedure from Example 1, substituting thiazole-5-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (80% yield).

MS (ESI): m/z=757.1 [M+H].

Example 32

Compound of formula B, wherein R=

(compound 61).

The title compound was prepared using the procedure from Example 1, substituting 1,3-dimethyl-1H-pyrazole-4-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (34% yield).

MS (ESI): m/z=768.1 [M+H].

Example 33

Compound of formula B, wherein R=

(compound 46).

The title compound was prepared using the procedure from Example 1, substituting cinnoline-4-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (54% yield).

MS (ESI): m/z=802.1 [M+H].

Example 34

Compound of formula B, wherein R=

(compound 47).

The title compound was prepared using the procedure from Example 1, substituting pyridazine-3-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (68% yield).

MS (ESI): m/z=752.1 [M+H].

Example 35

Compound of formula B, wherein R=

(compound 48).

The title compound was prepared using the procedure from Example 1, substituting 3-methylisoxazole-5-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (34% yield).

MS (ESI): m/z=755.1 [M+H].

Example 36

Compound of formula B, wherein R=

(compound 49).

The title compound was prepared using the procedure from Example 1, substituting 4-methylpyrimidine-5-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (77% yield).

MS (ESI): m/z=766.1 [M+H].

Example 37

Compound of formula B, wherein R=

(compound 51).

The title compound was prepared using the procedure from Example 1, substituting 2,4-dimethylpyrimidine-5-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (39% yield).

MS (ESI): m/z=780.1 [M+H].

Example 38

Compound of formula B, wherein R=

(compound 52).

The title compound was prepared using the procedure from Example 1, substituting pyrimidine-4-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (32% yield).

MS (ESI): m/z=752.1 [M+H].

Example 39

Compound of formula B, wherein R=

The title compound was prepared using the procedure from Example 1, substituting 1-methyl-1H-pyrazole-5-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (50% yield).

MS (ESI): m/z=754.2 [M+H].

Example 40

Compound of formula B, wherein R=

(compound 53).

The title compound was prepared using the procedure from Example 1, substituting 1-methyl-1H-pyrazole-4-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (92% yield).

MS (ESI): m/z=754.2 [M+H].

Example 41

Compound of formula B, wherein R=

(compound 55).

The title compound was prepared using the procedure from Example 1, substituting 3,6-dimethylpyrazine-2-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (68% yield).

MS (ESI): m/z=780.1 [M+H].

Example 42

Compound of formula B, wherein R=

(compound 57).

The title compound was prepared using the procedure from Example 1, substituting 6-methylpyrazine-2-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (54% yield).

MS (ESI): m/z=766.2 [M+H].

Example 43

Compound of formula B, wherein R=

(compound 58).

The title compound was prepared using the procedure from Example 1, substituting 3-methylpyrazine-2-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (35% yield).

MS (ESI): m/z=766.1 [M+H].

Example 44

Compound of formula B, wherein R=

(compound 59).

The title compound was prepared using the procedure from Example 1, substituting thiazole-2-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (13% yield).

MS (ESI): m/z=757.1 [M+H].

Example 45

Compound of formula B, wherein R=

(compound 60).

The title compound was prepared using the procedure from Example 1, substituting 1,5-dimethyl-1H-1,2,3-triazole-4-carboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (43% yield).

MS (ESI): m/z=769.2 [M+H].

Example 46

Compound of formula B, wherein R=

(compound 8).

The title compound was prepared using the procedure from Example 1, substituting 3,3-dimethylbutanoic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (66% yield).

MS (ESI): m/z=744.2 [M+H].

Example 47

Compound of formula B, wherein R=

(compound 10).

The title compound was prepared using the procedure from Example 1, substituting 2-cyclopentylacetic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (39% yield).

MS (ESI): m/z=756.2 [M+H].

Example 48

Compound of formula B, wherein R=

(compound 11).

The title compound was prepared using the procedure from Example 1, substituting 2-cyclopropylacetic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (42% yield).

MS (ESI): m/z=728.2 [M+H].

Example 49

Compound of formula B, wherein R=

(compound 12).

The title compound was prepared using the procedure from Example 1, substituting 1-methylcyclopropanecarboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (39% yield).

MS (ESI): m/z=728.2 [M+H].

Example 50

Compound of formula B, wherein R=

(compound 13).

The title compound was prepared using the procedure from Example 1, substituting 2,2-dimethylbutanoic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (43% yield).

MS (ESI): m/z=744.2 [M+H].

Example 51

Compound of formula B, wherein R=

(compound 19).

The title compound was prepared using the procedure from Example 1, substituting pivalic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (54% yield).

MS (ESI): m/z=730.2 [M+H].

Example 52

Compound of formula B, wherein R=

(compound 20).

The title compound was prepared using the procedure from Example 1, substituting (R)-2-hydroxybutanoic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (48% yield).

MS (ESI): m/z=732.2 [M+H].

Example 53

Compound of formula B, wherein R=

(compound 21).

The title compound was prepared using the procedure from Example 1, substituting (R)-2-cyclohexyl-2-hydroxyacetic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (41% yield).

MS (ESI): m/z=786.1[M+H].

Example 54

Compound of formula B, wherein R=

(compound 22).

The title compound was prepared using the procedure from Example 1, substituting (S)-2-hydroxy-4-methylpentanoic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (52% yield).

MS (ESI): m/z=760.2 [M+H].

Example 55

Compound of formula B, wherein R=

(compound 23).

The title compound was prepared using the procedure from Example 1, substituting 2-phenylcyclopropanecarboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (54% yield).

MS (ESI): m/z=790.1 [M+H].

Example 56

Compound of formula B, wherein R=

(compound 24).

The title compound was prepared using the procedure from Example 1, substituting cyclopropanecarboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (55% yield).

MS (ESI): m/z=714.2 [M+H].

Example 57

Compound of formula B, wherein R=

(compound 28).

The title compound was prepared using the procedure from Example 1, substituting 2-hydroxy-2-methylpropanoic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (51% yield).

MS (ESI): m/z=732.1 [M+H].

Example 58

Compound of formula B, wherein R=

(compound 43).

The title compound was prepared using the procedure from Example 1, substituting 2-methyl-2-phenylpropanoic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (73% yield).

MS (ESI): m/z=792.2 [M+H].

Example 59

Compound of formula B, wherein R=

(compound 50).

The title compound was prepared using the procedure from Example 1, substituting 1-phenylcyclopropanecarboxylic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (76% yield).

MS (ESI): m/z=790.2 [M+H].

Example 60

Compound of formula B, wherein R=

(compound 54).

The title compound was prepared using the procedure from Example 1, substituting (S)-2-cyclohexyl-2-hydroxyacetic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (49% yield).

MS (ESI): m/z=786.1 [M+H].

Example 61

Compound of formula B, wherein R=

(compound 56).

The title compound was prepared using the procedure from Example 1, substituting (S)-2-hydroxy-3,3-dimethylbutanoic acid for 5-methylisoxazole-3-carboxylic acid. The residue was purified by reverse phase chromatography to give the desired product (42% yield).

MS (ESI): m/z=760.2 [M+H].

To a solution of Compound A (100 mg, 0.155 mmol) in dichloromethane (1 mL) at room temperature was added 4-nitrophenyl carbonochloridate (31.2 mg, 0.155 mmol) followed by diisopropylethylamine (30 mg, 0.232 mmol). The reaction mixture was evaporated under reduced pressure and the residue purified by column chromatography on silica gel to provide Compound C (126 mg, 100% yield).

Example 62

Compound of formula B, wherein R=

(compound 57).

To a solution of Compound C (10 mg, 0.012 mmol) in dimethylformamide (0.166 mL) stirring at room temperature was added morpholine (1.1 mg, 0.012 mmol). The reaction mixture was stirred at room temperature for 16 hours and then evaporated under reduced pressure. The residue was purified by reverse phase chromatography to give the desired product (6.8 mg, 73% yield).

MS (ESI): m/z=759.2 [M+H].

Example 63

Compound of formula B, wherein R=

(compound 65).

The title compound was prepared using the procedure from Example 62, substituting pyrrolidine for morpholine. The residue was purified by reverse phase chromatography to give the desired product (92% yield).

MS (ESI): m/z=743.2 [M+H].

Example 64

Compound of formula B, wherein R=

(compound 66).

The title compound was prepared using the procedure from Example 62, substituting piperidine for morpholine. The residue was purified by reverse phase chromatography to give the desired product (43% yield).

MS (ESI): m/z=757.2 [M+H].

Example 65

Compound of formula B, wherein R=

(compound 67).

The title compound was prepared using the procedure from Example 62, substituting azepane for morpholine. The residue was purified by reverse phase chromatography to give the desired product (80% yield).

MS (ESI): m/z=771.2 [M+H].

Example 66

Compound of formula B, wherein R=

(compound 69).

The title compound was prepared using the procedure from Example 62, substituting thiomorpholinefor morpholine. The residue was purified by reverse phase chromatography to give the desired product (35% yield).

MS (ESI): m/z=775.1 [M+H].

Example 67

Compound of formula B, wherein R=

(compound 70).

The title compound was prepared using the procedure from Example 62, substituting 1-methylpiperazine for morpholine. The residue was purified by reverse phase chromatography to give the desired product (25% yield).

MS (ESI): m/z=772.2 [M+H].

Example 68

Compound of formula B, wherein R=

(compound 68).

The title compound was prepared using the procedure from Example 62, dimethylamine for morpholine. The residue was purified by reverse phase chromatography to give the desired product (68% yield).

MS (ESI): m/z=717.1 [M+H].

Example 69

Compound of formula B, wherein R=

(compound 63).

The title compound was prepared using the procedure from Example 62, substituting piperazine for morpholine. The crude reaction mixture was evaporated under reduced pressure and then treated with 1 mL of 1 N HCL for 1 h. The reaction mixture was then evaporated under reduced pressure. The residue was purified by reverse phase chromatography to give the desired product (88% yield).

MS (ESI): m/z=758.1 [M+H].

The compounds of the present invention exhibit potent inhibitory properties against the HCV NS3 protease. The following examples describe assays in which the compounds of the present invention can be tested for anti-HCV effects.

Example 70 NS3/NS4a Protease Enzyme Assay

HCV protease activity and inhibition is assayed using an internally quenched fluorogenic substrate. A DABCYL and an EDANS group are attached to opposite ends of a short peptide. Quenching of the EDANS fluorescence by the DABCYL group is relieved upon proteolytic cleavage. Fluorescence is measured with a Molecular Devices Fluoromax (or equivalent) using an excitation wavelength of 355 nm and an emission wavelength of 485 nm.

The assay is run in Corning white half-area 96-well plates (VWR 29444-312 [Corning 3693]) with full-length NS3 HCV protease 1b tethered with NS4A cofactor (final enzyme concentration 1 to 15 nM). The assay buffer is complemented with 10 μM NS4A cofactor Pep 4A (Anaspec 25336 or in-house, MW 1424.8). RET S1 (Ac-Asp-Glu-Asp(EDANS)-Glu-Glu-Abu-[Coo]Ala-Ser-Lys-(DABCYL)-NH₂ (SEQ ID NO: 4), AnaSpec 22991, MW 1548.6) is used as the fluorogenic peptide substrate. The assay buffer contains 50 mM Hepes at pH 7.5, 30 mM NaCl and 10 mM BME. The enzyme reaction is followed over a 30 minutes time course at room temperature in the absence and presence of inhibitors.

The peptide inhibitors HCV Inh 1 (Anaspec 25345, MW 796.8) Ac-Asp-Glu-Met-Glu-Glu-Cys-OH (SEQ ID NO: 5), [−20° C.] and HCV Inh 2 (Anaspec 25346, MW 913.1) Ac-Asp-Glu-Dif-Cha-Cys-OH (SEQ ID NO: 6), are used as reference compounds.

IC₅₀ values are calculated using XLFit in ActivityBase (IDBS) using equation 205: y=A+((B−A)/(1+((C/x)^D))).

Example 71 Cell-Based Replicon Assay

Quantification of HCV replicon RNA (HCV Cell Based Assay) is accomplished using the Huh 11-7 cell line (Lohmann, et al Science 285:110-113, 1999). Cells are seeded at 4×10³ cells/well in 96 well plates and fed media containing DMEM (high glucose), 10% fetal calf serum, penicillin-streptomycin and non-essential amino acids. Cells are incubated in a 7.5% CO₂ incubator at 37° C. At the end of the incubation period, total RNA is extracted and purified from cells using Ambion RNAqueous 96 Kit (Catalog No. AM1812). To amplify the HCV RNA so that sufficient material can be detected by an HCV specific probe (below), primers specific for HCV (below) mediate both the reverse transcription of the HCV RNA and the amplification of the cDNA by polymerase chain reaction (PCR) using the TaqMan One-Step RT-PCR Master Mix Kit (Applied Biosystems catalog no. 4309169). The nucleotide sequences of the RT-PCR primers, which are located in the NS5B region of the HCV genome, are the following:

HCV Forward primer “RBNS5bfor” 5′GCTGCGGCCTGTCGAGCT (SEQ ID NO: 1): HCV Reverse primer “RBNS5Brev” 5′CAAGGTCGTCTCCGCATAC. (SEQ ID NO 2)

Detection of the RT-PCR product is accomplished using the Applied Biosystems (ABI) Prism 7500 Sequence Detection System (SDS) that detects the fluorescence that is emitted when the probe, which is labeled with a fluorescence reporter dye and a quencher dye, is degraded during the PCR reaction. The increase in the amount of fluorescence is measured during each cycle of PCR and reflects the increasing amount of RT-PCR product. Specifically, quantification is based on the threshold cycle, where the amplification plot crosses a defined fluorescence threshold. Comparison of the threshold cycles of the sample with a known standard provides a highly sensitive measure of relative template concentration in different samples (ABI User Bulletin #2 Dec. 11, 1997). The data is analyzed using the ABI SDS program version 1.7. The relative template concentration can be converted to RNA copy numbers by employing a standard curve of HCV RNA standards with known copy number (ABI User Bulletin #2 Dec. 11, 1997).

The RT-PCR product was detected using the following labeled probe:

(SEQ ID NO: 3) 5′ FAM-CGAAGCTCCAGGACTGCACGATGCT-TAMRA

FAM=Fluorescence reporter dye.

TAMRA:=Quencher dye.

The RT reaction is performed at 48° C. for 30 minutes followed by PCR. Thermal cycler parameters used for the PCR reaction on the ABI Prism 7500 Sequence Detection System are: one cycle at 95° C., 10 minutes followed by 40 cycles each of which include one incubation at 95° C. for 15 seconds and a second incubation for 60° C. for 1 minute.

To normalize the data to an internal control molecule within the cellular RNA, RT-PCR is performed on the cellular messenger RNA glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The GAPDH copy number is very stable in the cell lines used. GAPDH RT-PCR is performed on the same RNA sample from which the HCV copy number is determined. The GAPDH primers and probes are contained in the ABI Pre-Developed TaqMan Assay Kit (catalog no. 4310884E). The ratio of HCV/GAPDH RNA is used to calculate the activity of compounds evaluated for inhibition of HCV RNA replication.

Activity of Compounds as Inhibitors of HCV Replication (Cell Based Assay) in Replicon Containing Huh-7 Cell Lines.

The effect of a specific anti-viral compound on HCV replicon RNA levels in Huh-11-7 cells is determined by comparing the amount of HCV RNA normalized to GAPDH (e.g. the ratio of HCV/GAPDH) in the cells exposed to compound versus cells exposed to the DMSO vehicle (negative control). Specifically, cells are seeded at 4×10³ cells/well in a 96 well plate and are incubated either with: 1) media containing 1% DMSO (0% inhibition control), or 2) media/1% DMSO containing a fixed concentration of compound. 96 well plates as described above are then incubated at 37° C. for 4 days (EC50 determination). Percent inhibition is defined as: % Inhibition=100−100*S/Cl

where

S=the ratio of HCV RNA copy number/GAPDH RNA copy number in the sample;

Cl=the ratio of HCV RNA copy number/GAPDH RNA copy number in the 0% inhibition control (media/1% DMSO).

The dose-response curve of the inhibitor is generated by adding compound in serial, three-fold dilutions over three logs to wells starting with the highest concentration of a specific compound at 1.5 uM and ending with the lowest concentration of 0.23 nM. Further dilution series (500 nM to 0.08 nM for example) is performed if the EC50 value is not positioned well on the curve. EC50 is determined with the IDBS Activity Base program “XL Fit” using a 4-paramater, non-linear regression fit (model # 205 in version 4.2.1, build 16).

In the above assays, representative compounds of the present invention were found to have HCV replication inhibitory activity and HCV NS3 protease inhibitory activity. These compounds were also effective in inhibiting HCV NS3 proteases of different HCV genotypes including genotypes 1, 2, 3 and 4.

Compounds of the invention were tested in the above assays (Examples 1-72). Exemplary compounds disclosed herein were found to have activities in the ranges of <=0.2 nM-100 nM in the NS3/NS4a Protease Enzyme Assay and <=0.2 nM-100 nM in the Cell-Based Replicon Assay.

Although the invention has been described with respect to various preferred embodiments, it is not intended to be limited thereto, but rather those skilled in the art will recognize that variations and modifications may be made therein which are within the spirit of the invention and the scope of the appended claims. 

1. A compound of Formula I:

or a pharmaceutically acceptable salt thereof, wherein R is selected from the group consisting of:

and

 denotes a carbon-carbon single or double bond.
 2. A compound according to claim 1, represented by formula III:

or a pharmaceutically acceptable salt thereof wherein R is as defined in claim
 1. 3. The compound according to claim 1, or a pharmaceutically acceptable salt thereof, represented by formula II, wherein R is delineated in TABLE 1: TABLE 1 II

Compound # R 1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70


4. The compound according to claim 1, selected from the compounds represented by formula III, or a pharmaceutically acceptable salt thereof, wherein R for each compound is delineated in TABLE 2: TABLE 2 III

Compound # R 71

72


5. A pharmaceutical composition comprising an inhibitory amount of a compound according to claim 1 in combination with a pharmaceutically acceptable carrier or excipient.
 6. A method of treating a viral infection in a subject, comprising administering to the subject an inhibitory amount of a pharmaceutical composition according to claim
 5. 7. The method of claim 6, wherein the viral infection is hepatitis C.
 8. A method of inhibiting the replication of hepatitis C virus, the method comprising supplying a hepatitis C viral NS3 protease inhibitory amount of the pharmaceutical composition of claim
 5. 9. The method of claim 7 further comprising administering concurrently an additional anti-hepatitis C virus agent.
 10. The method of claim 9, wherein said additional anti-hepatitis C virus agent is selected from the group consisting of: α-interferon, β-interferon, ribavarin, and adamantine.
 11. The method of claim 9, wherein said additional anti-hepatitis C virus agent is an inhibitor of hepatitis C virus helicase, polymerase, metalloprotease, or IRES.
 12. The pharmaceutical composition of claim 5, further comprising another anti-HCV agent.
 13. The pharmaceutical composition of claim 5, further comprising an agent selected from interferon, ribavirin, amantadine, another HCV protease inhibitor, an HCV polymerase inhibitor, an HCV helicase inhibitor, or an internal ribosome entry site inhibitor.
 14. The pharmaceutical composition of claim 5, further comprising pegylated interferon.
 15. The pharmaceutical composition of claim 5, further comprising another anti-viral, anti-bacterial, anti-fungal or anti-cancer agent, or an immune modulator. 